1. Technical Field
This disclosure relates generally to accessing data on a physical recording medium, and more specifically to determining statistics associated with the storage of data on such a medium.
2. Description of the Related Art
A set of data is typically written to solid-state storage media by performing an erase operation on a group of memory cells followed by a program operation on those cells. Because of the small size of these cells and the high voltages used to perform these operations, the transistors within the cells begin to degrade over time such that only a limited number of erase operations and program operations can be performed. To improve the longevity of memory cells, modern storage systems may implement a log-structured storage to ensure that writes to cells are more evenly distributed across the storage to produce better wear leveling (as opposed to writing particular cells frequently while other cells go unused).
While storing data in this manner can improve wear leveling, memory cells may still degrade to the point that they are no longer able to store information accurately. That is, a particular value may be written to a block of memory cells; however, when it is subsequently read, the value may not be retrievable upon being read from memory (or may be read incorrectly). Even still, memory cells that have minimal wear may still have limits on how long they can maintain a charge due to leakage current. As a result, in some instances, various statistics may be maintained to determine the reliability of memory cells with a storage device.